diff --git a/src/mame/video/namcofl.cpp b/src/mame/video/namcofl.cpp
index 9a4f2be52e7..a0a1cacd2c6 100644
--- a/src/mame/video/namcofl.cpp
+++ b/src/mame/video/namcofl.cpp
@@ -60,19 +60,29 @@ void namcofl_state::RozCB(uint16_t code, int *tile, int *mask, int which)
 
 uint32_t namcofl_state::screen_update_namcofl(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
 {
+	/* compute window for custom screen blanking */
+	rectangle clip;
+	//004c 016b 0021 0101 004a 0060 (finalapr*)
+	//004b 016b 0021 0101 0144 0047 (speedrcr)
+	clip.min_x = m_c116->get_reg(0) - 0x4b;
+	clip.max_x = m_c116->get_reg(1) - 0x4b - 1;
+	clip.min_y = m_c116->get_reg(2) - 0x21;
+	clip.max_y = m_c116->get_reg(3) - 0x21 - 1;
+	/* intersect with master clip rectangle */
+	clip &= cliprect;
 	int pri;
 
 	bitmap.fill(m_c116->black_pen(), cliprect );
 
 	for( pri=0; pri<16; pri++ )
 	{
-		m_c169roz->draw(screen, bitmap, cliprect, pri);
+		m_c169roz->draw(screen, bitmap, clip, pri);
 		if ((pri & 1) == 0)
 		{
-			m_c123tmap->draw(screen, bitmap, cliprect, pri >> 1);
+			m_c123tmap->draw(screen, bitmap, clip, pri >> 1);
 		}
 
-		m_c355spr->draw(screen, bitmap, cliprect, pri );
+		m_c355spr->draw(screen, bitmap, clip, pri );
 	}
 
 	return 0;